FreeBSD's current ZFS version (v15?) doesn't even support raidz3 and deduping, which was released quite some time back, so it certainly wouldn't be recent enough to support encryption.

Well, yes and no - FreeBSD-CURRENT (which will eventually be released as the 9.x branch) has had v28 since January. The stable branches (7.x and 8.x) are still on v15, though.

I have no idea when they'll import v30, but I expect it'll happen eventually. Alternatively, it's possible to combine ZFS with e.g. GELI to get an encrypted FreeBSD system today - so if they have enough man-hours, they can add that to FreeNAS instead of waiting.

Well, yes and no - FreeBSD-CURRENT (which will eventually be released as the 9.x branch) has had v28 since January. The stable branches (7.x and 8.x) are still on v15, though.

Well yes, but you'd be insane to run FreeBSD-CURRENT on a production storage array anyway, so your point is moot.

I have no idea when they'll import v30, but I expect it'll happen eventually. Alternatively, it's possible to combine ZFS with e.g. GELI to get an encrypted FreeBSD system today - so if they have enough man-hours, they can add that to FreeNAS instead of waiting.

Well yes, but you'd be insane to run FreeBSD-CURRENT on a production storage array anyway, so your point is moot.

Not quite - it shows that it's already in there and just waiting for 9 to mature enough for a release. As of right now, it's quite stable - there are people using it in not-entirely-critical production, including me. (I've got a ZFS mirror with dedup and compression on a lab fileserver. It's just for working copies, but I honestly trust it more than how we store the reference copies.)

I didn't know about GELI. Thank you

I think someone needs to make a "nice FreeBSD features you might not know about"-list.
(I'd thrown in HAST as well - I don't use it, but I'd like to.)